Method and device for feeding of cold pilger mills

ABSTRACT

The invention refers to a method and apparatus for feeding shells of variable lengths in a pilger mill to effect optimum efficiency. When the entry pusher of the mill starts moving the length of newly fed shell is measured and this measurement is transmitted to a memory counter, and by means of a program control the distance travelled by the feed carriage is regulated to the length of the newly fed shell, whereby the feed carriage moves only far enough so that on its return to a starting position a space is left which is equal to the length of the newly fed shell.

United States Patent Gerretz et al.

[ 1 May 2,1972

[54] METHOD AND DEVICE FOR FEEDING OF COLD PILGER MILLS [72] inventors: Josef Gerretz, Suechteln; Willi l-lngedorn; Karl-Heinz Kemmerllng, both of Moenchengladbach, all of Germany [73] Assignee: Wean Industries, Inc., Youngstown, Ohio [22] Filed: Oct. 21, 1970 [2 1] Appl. No.: 82,739

[52] U.S. Cl ..72/l4, 72/208, 72/214, 72/250 [51] Int. Cl .,B21b 21/04 [58] Field oi Search ..72/l4, 208, 214, 215, 250, 72/252 L 7 x Le [5 6] References Cited UNITED STATES PATENTS 2,914,973 12/1959 Crane et a]. ..72/208 Primary Examiner-Lowell A. Larson Attorney-Michael Williams [57] ABSTRACT The invention refers to a method and apparatus for feeding shells of variable lengths in a pilger mill to effect optimum efficiency. When the entry pusher of the mill starts moving the length of newly fed shell is measured and this measurement is transmitted to a memory counter, and by means of a program control the distance travelled by the feed carriage is regulated to the length of the newly fed shell, whereby the feed carriage moves only far enough so that on its return to a starting position a space is left which is equal to the length of the newly fed shell.

6 Claims, 4 Drawing Figures METHOD AND DEVICE FOR FEEDING OF COLD PILGER MILLS BACKGROUND AND SUMMARY Insofar as we are aware, pilger mills are usually laid out to handle only a certain maximum length of shell. As long as shells equal to such certain maximum length are processed, the mill operates at maximum efiiciency. However, if such a mill is used for feeding shells of variable lengths, the degree of efficiency drops considerably due to the travel length as originally provided.

It is therefore the principal object of our invention to permit maximum efficiency in the feeding operation of a pilger mill even when working on shells of variable length. Briefly, the invention comprises the measurement of a shell as it is moved forwardly by a pusher device, transmitting the measurement to a memory counter having a nulling device, and by means of a program controller regulating the feeding movement of a feed carriage to the length of the new shell, so that the latter will closely fit within the space between the feed carriage and the end of the shell already being worked in the pilger dies.

DESCRIPTION OF THE DRAWING In the drawing accompanying this specification and forming a part of this application, there is shown, for purposes of illustration, an embodiment which our invention may assume, and in this drawing:

FIG. 1 shows the feeding mechanism as seen from the top as it is being loaded with a shell whose length is shorter than that for which the mill is set up,

FIG. 2 shows the measuring process of the short shell in the entry pusher trough, as viewed from the top,

FIG. 3 shows the feeding mechanism, as viewed from the top, whereby the new shell is shown after the entry push operation is completed, and

FIG. 4 is a diagrammatic representation of the control mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring particularly to FIG. 1, the preceding shell 2 is shown in the process of being reduced by the usual pilger rocking dies 1, the usual mandrel (not shown) being disposed within the shell 2. In known manner, a feed carriage 4 engages the free end of the shell 2 and feeds it through the dies. The feed carriage may be of conventional design and driven in opposite directions by a rotatable elongated feed screw 4a (FIG. 4) which has engagement with a nut carried by the carriage 4. The feed carriage may be opened, in usual manner, for feeding of a new shell axially therethrough for disposition between such carriage and the free end of the preceding shell. All of the foregoing is well known in the art and need not be described in detail.

As seen in FIG. 1, the new shell 3 is moved from its dotted line position to disposition within the usual inlet trough 12. A plurality of switches (such as switches closed by the weight of the shell) are disposed longitudinally of the trough. In the illustrated embodiment, three switches 6, 7 and 8 are disposed along the trough to span a distance corresponding to the length "L" of the longest shell to be fed.

When the new shell 3 is disposed within the inlet trough, it activates one or more of the switches 6, 7 and 8 to start the drive of the entry pusher from its starting position defined by the limit switch 13 to move the pusher to the right as viewed in FIG. 1. The drive for the entry pusher may take the form of a cable 15 (see FIG. 4) trained (as is well known in the art) over spaced pulleys 16,17 and wound on a drum 18 which is rotated by a motor (not shown). To drive the entry pusher to the right, the drum is driven in the direction of the arrow to wind the cable reach 20 onto the drum and to unwind the cable reach 21 from the drum. To return the entry pusher, the drum is driven in the opposite direction until it strikes the limit switch 13, whereupon the drive to the drum 18 is halted. All of this is conventional and need not be described in further detail.

As seen in FIG. 1, the end 5a of the entry pusher 5 is spaced some distance from the adjoining end of the new shell 3 disposed in the trough 12. In FIG. 2, the entry pusher end has engaged the adjoining end of the new shell 3 and has pushed this shell to the right to make contact with the limit switch 9, and activation of the latter switch stops the drive motor for the drum l8 and thus stops movement of the entry pusher 5 to the right.

Referring to FIG. 4, the drum 18 has a drive connection to a device 22 which is operable to measure the length of the new shell 3. In the disclosed embodiment, such measurement is effected by the revolution of the drum during the time it moves the entry pusher to the right from its starting point at the limit switch 13. The device 22 may take the form of a Rotopulser made by the Louis Allis division of Litton Industries.

The Rotopulser 22 feeds its measuring information to a calculator device 23 which interpolates such information and feeds it to a second device 24 which may be similar to the device 22 and therefore may also take the form of a Rotopulser. The calculator device 23 may take the form of an add-subtract controller which is also made by the aforementioned Louis Allis division. The second Rotopulser has connection to mechanism M for rotating the feed screw 4a which drives the feed carriage and regulates the movement of the latter from a starting position defined by a limit switch 11 toward the pilger dies an amount equal to the length of the shell 3.

In operation, and assuming the pilger mill is set for feeding shells of the maximum length L" shown in FIG. 2, when the shorter shell 3 is disposed in the trough 12 and activates the switches 7 and 8 (in this case) the drive for the drum I8 is started and the Rotopulser 22 counts the drum revolutions required to push the shell 3 until its leading end strikes the limit switch 9. Since the drum 18 revolves a greater amount in order to push the shorter shell 3 against the limit switch 9 than it would to push a longer shell defined by the dimension L, the Rotopulser 22 reflects this longer movement, designated X" in FIG. 2, and sends its information to the calculator 23. The latter automatically subtracts the distance X from the distance L and feeds this corrected information to the Rotopulser 24.

After the feed carriage 4 has travelled the distance Le (the length of the new shell) to the right (FIG. 2) from its starting position at switch 11, Rotopulser 24, through an automatic sequence control which may be of commercial form, interrupts the drive of the pilger dies, returns the feed carriage 4 in opened condition to its starting position at switch ll, opens the mandrel lock and pushes the new shell 3, by means of the entry pusher 5, through the feed carriage onto the mandrel while the shell 2 already being processed and the mandrel are locked by the stopped dies 1, until both shells 2 and 3 contact, whereupon the feed carriage is again closed, the pusher carriage returned to its starting position at switch 13, the mandrel lock is again closed and the pilger dies again operated to work on the preceding shell as the feed carriage 4 moves to push both shells to the right.

The original mill design requires the feed carriage 4 to travel the distance between safety limit switch 10 and switch 1 1 and switch 10 may be adjusted for a given maximum length of a certain production run. However, when shorter shells are also fed, there is an undesired time delay while the mill is stopped, and our invention pennits a decrease in this time loss and thus provides for maximum efiiciency in the mill when feeding shells that are shorter than the maximum length for which the mill is set.

We claim:

1. The method of feeding shells of predetennined length and shorter lengths to the dies of a pilger mill, comprising feeding a shell of shorter length in a direction toward said dies by means of an entry pusher, measuring the length of the newly fed shell while a feed carriage is moving a preceding shell through the pilger dies, limiting movement of said feed carriage from a starting position to the length of said newly fed shell, stopping action of the pilger dies on said preceding shell when said feed carriage has moved said limited amount,

returning said feed carriage to said starting.position,-pushing the newly fed shell to fit in the space between said feed carriage and the free end of said preceding shell, and again activating said pilger dies and moving said feed carriage in a direction toward said pilger dies to push said newly fed shell and said preceding shell against which said newly fed shell is abutted toward and through said pilger dies.

2. The method of claim 1 and further including the return of said entry pusher to a starting position prior to reactivation of said pilger dies.

3. Apparatus for feeding shells of predetermined length and shorter lengths to the dies of a pilger mill, comprising an entry pusher for pushing a shell of certain length in a direction toward said pilger dies, a feed carriage for pushing a preceding shell through said pilger dies, means for measuring the length of said certain length shell, means for regulating the movement of said feed carriage in a direction toward said pilger dies from a predetermined starting position to any amount between said starting position and a maximum position, and calculator means affected by the measured length of said certain length shell and correspondingly affecting said regulating means to move said feed carriage from its starting position a distance corresponding to said measured length, whereby said feed carriage may be returned to its starting position, said certain length shell may be interposed between said feed carriage and said preceding shell, and said feed carriage again moved toward said pilger dies to feed said certain length shell, and the preceding shell against which it is abutted, toward and through said pilger dies.

4. Apparatus for feeding shells of predetermined length and shorter lengths to the conventional dies of a pilger mill which operate in conjunction with a conventional mandrel, comprising an entry pusher for pushing a shell of certain length in a direction toward said pilger dies, a feed carriage for pushing a preceding shell through said pilger dies, at first measuring device affected by pushing movement of entry pusher for measuring the length of said certain length shell, a second measuring device for regulating movement of said feed carriage in a direction toward said pilger dies from a predetermined starting position to any amount between said starting position and a maximum position corresponding to shells of said predetermined length, and a calculating device afi'ected by said first measuring device and affecting said second measuring device, operable when said certain length shell is shorter than said predetermined length, to limit movement of said feed carriage from said starting position to an amount equal to the length of said shorter shell, whereby said feed carriage may be returned to its starting position, said shorter shell may be interposed between said feed carriage and said preceding shell, and said feed carriage again moved toward said pilger dies to feed said shorter shell and said preceding shell against which it is abutted, toward and through said pilger dies.

5. The construction of claim 4 wherein pushing movement of said entry pusher is initiated when said certain length shell is disposed within the entry trough of said pilger mill.

6. The construction according to claim 4 and further including means to perform the following operations: halt operation of said pilger dies on said preceding shell, open said feed carriage and return it to its starting position, open the mandrel lock, activate said entry pusher to push said shorter shell through said feed carriage to dispose it in position between said feed carriage and the adjoining end of said preceding shell, close said feed carriage, return said entry pusher to a starting position, close the mandrel lock, start operation of said pilger dies on said preceding shell and move said feed carriage to push said shorter shell and said preceding shell against which it is abutted towards and through said pilger dies. 

1. The method of feeding shells of predetermined length and shorter lengths to the dies of a pilger mill, comprising feeding a shell of shorter length in a direction toward said dies by means of an entry pusher, measuring the length of the newly fed shell while a feed carriage is moving a preceding shell through the pilger dies, limiting movement of said feed carriage from a starting position to the length of said newly fed shell, stopping action of the pilger dies on said preceding shell when said feed carriage has moved said limited amount, returning said feed carriage to said starting position, pushing the newly fed shell to fit in the space between said feed carriage and the free end of said preceding shell, and again activating said pilger dies and moving said feed carriage in a direction toward said pilger dies to push said newly fed shell and said preceding shell against which said newly fed shell is abutted toward and through said pilger dies.
 2. The method of claim 1 and further including the return of said entry pusher to a starting position prior to reactivation of said pilger dies.
 3. Apparatus for feeding shells of predetermined length and shorter lengths to the dies of a pilger mill, comprising an entry pusher for pushing a shell of certain length in a direction toward said pilger dies, a feed carriage for pushing a preceding shell through said pilger dies, means for measuring the length of said certain length shell, means for regulating the movement of said feed carriage in a direction toward said pilger dies from a predetermined starting position to any amount between said starting position and a maximum position, and calculator means affected by the measured length of said certain length shell and correspondingly affecting said regulating means to move said feed carriage from its starting position a distance corresponding to said measured length, whereby said feed carriage may be returned to its starting position, said certain length shell may be interposed between said feed carriage and said preceding shell, and said feed carriage again moved toward said pilger dies to feed said certain length shell, and the preceding shell against which it is abutted, toward and through said pilger dies.
 4. Apparatus for feeding shells of predetermined length and shorter lengths to the conventional dies of a pilger mill which operate in conjunction with a conventional mandrel, comprising an entry pusher for pushing a shell of certain length in a direction toward said pilger dies, a feed carriage for pushing a preceding shell through said pilger dies, a first measuring device affected by pushing movement of entry pusher for measuring the length of said certain length shell, a second measuring device for regulating movement of said feed carriage in a direction toward said pilger dies from a predetermined starting position to any amount between said starting position and a maximum position corresponding to shells of said predetermined length, and a calculating device affected by said first measuring device and affecting said second measuring device, operable when said certain length shell is shorter than said predetermined length, to limit movement of said Feed carriage from said starting position to an amount equal to the length of said shorter shell, whereby said feed carriage may be returned to its starting position, said shorter shell may be interposed between said feed carriage and said preceding shell, and said feed carriage again moved toward said pilger dies to feed said shorter shell and said preceding shell against which it is abutted, toward and through said pilger dies.
 5. The construction of claim 4 wherein pushing movement of said entry pusher is initiated when said certain length shell is disposed within the entry trough of said pilger mill.
 6. The construction according to claim 4 and further including means to perform the following operations: halt operation of said pilger dies on said preceding shell, open said feed carriage and return it to its starting position, open the mandrel lock, activate said entry pusher to push said shorter shell through said feed carriage to dispose it in position between said feed carriage and the adjoining end of said preceding shell, close said feed carriage, return said entry pusher to a starting position, close the mandrel lock, start operation of said pilger dies on said preceding shell and move said feed carriage to push said shorter shell and said preceding shell against which it is abutted towards and through said pilger dies. 